We propose to 1) determine which types of malignant tumors secrete degradative enzymes capable of attacking connective tissue ground substance proteoglycans. 2) determine the nature of these enzymes and their mode of substrate degradation. 3) further refine an assay procedure already worked out in preliminary fashion, which may have a prognostic potential. 4) attempt to block the release of such enzymes by the use of zinc ions as a possible chemotheraphy.